Embed Size (px)
Citation preview
Mikhail Nikolchak
EFFICIENCY OF AIR HANDLING UNIT IN X-BUILDING
Bachelor’s Thesis
Building Services Engineering
April 2012
DESCRIPTION
Date of the bachelor's thesis
Author
Mikhail Nikolchak
Degree programme and option
Building Services Engineering
Name of the bachelor's thesis
Efficiency of air handling unit of X-building
Abstract
The subject of this thesis is energy efficiency of air handling unit in X-building of MUAS. One of the aims of this
work is to describe different equipment, which is in common to use in air handling. Some processes, which
take place in air handling unit, will be described. Next, and main aim is to compare existing AHU with
alternatives and define the most effective configuration.
It was necessary to make some measurements and calculations to compare AHUs. All measurements are
described and calculations were made according to the National Building Code of Finland D5 and Ministry of
environment of Finland.
As a result of comparison AHU equipped with counter-flow plate heat recovery was defined as the most
effective variant with annual energy efficiency of whole ventilation system almost 63%.
Subject headings, (keywords)
Ventilation, heat recovery unit, efficiency of heat recovery, air handling
Pages Language URN
30
English
Remarks, notes on appendices
Tutor
Mika Kuusela
Employer of the bachelor's thesis
CONTENTS
NOMENCLATURE ....................................................................................................... 1
1. INTRODUCTION ...................................................................................................... 2
2. THEORETICAL BACKGROUND ........................................................................... 4
2.1 Air filters............................................................................................................... 4
2.2 Fans ....................................................................................................................... 5
2.2.1 Axial flow ...................................................................................................... 6
2.2.2 Centrifugal or radial flow ............................................................................... 7
2.2.3 Mixed flow ..................................................................................................... 7
2.3 Heating coils ......................................................................................................... 8
2.4 Cooling coils ....................................................................................................... 10
2.5 Humidifiers ......................................................................................................... 11
2.6 Dehumidifiers ..................................................................................................... 12
2.7 Energy recovery ventilation systems .................................................................. 12
2.7.1 Heat recovery ventilators ............................................................................. 13
2.7.1.1 Plate heat recovery ................................................................................ 13
2.7.1.2 Double coil heat recovery ..................................................................... 14
2.7.1.3 Heat pipe heat recovery ......................................................................... 15
2.7.2 Enthalpy recovery ventilators ...................................................................... 17
2.7.2.1 Rotating wheel heat recovery ................................................................ 18
2.7.2.2 Permeable membrane plate heat recovery ............................................. 19
3. MEASUREMENTS AND COMPAIRING ............................................................. 21
3.1 Measurements made by data loggers .................................................................. 21
3.2 Measuring of volume flow from WCs ................................................................ 22
4. CALCULATIONS AND COMPARING................................................................. 24
4.1 Order and description of calculations ................................................................. 24
4.2 Comparing of existing HRU with alternative ..................................................... 28
5. CONCLUSION ........................................................................................................ 30
BIBLIOGRAPHY ........................................................................................................ 31
Appendix 1 ................................................................................................................... 32
Appendix 2 ................................................................................................................... 36
Appendix 3 ................................................................................................................... 38
Appendix 4 ................................................................................................................... 39
Appendix 5 ................................................................................................................... 42
Appendix 6 ................................................................................................................... 43
Appendix 7 ................................................................................................................... 46
1
1
NOMENCLATURE
specific heat capacity;
d internal diameter of the duct
temperature ratio
actual temperature ratio
sum of heat recovery energy for all outdoor temperatures
energy recovered from ventilation
sum of energy needed for ventilation
net heating energy for ventilation
heating make up air in a space
heating of supply air in a space
volume flow of air stream
make-up air volume flow
density of the air
operation time during the day
temperature of inblown air
mean outdoor air temperature during month (given in D5)
temperature of exhaust air after heat recovery unit
indoor air temperature
temperature of supply air after heat recovery unit
outdoor air temperature
operation days during the week.
duration of certain outdoor temperature in hours
V velocity of air stream
2
2
1. INTRODUCTION
To achieve comfortable indoor climate, it is very important to have good designed
ventilation system according to all requirements.
There are two main types of ventilation systems: natural and mechanical ventilation.
To choose one of them you should make a chose about your priorities like efficiency
or economy. For example natural ventilation is low cost system but it can work in
wrong direction because it is based on pressure difference between indoor space and
outdoor conditions. This kind of system has not any fan or other forcing mechanisms.
So in case of unsatisfying weather conditions natural ventilation may works wrong. If
you need good performance ventilation system your chose should be - mechanical
ventilation. This type of ventilation is divided into two: mechanical exhaust,
mechanical supply and exhaust ventilation. The first one is cheaper than last, but it
may not meet requirements. Mechanical exhaust and supply ventilation systems are
the most expensive (as an investments, as an operation costs), but it has the best
performance. It is very useful to use heat recovery in air handling unit. It is a special
equipment which allows save a lot of energy on heating and cooling of supply air.
There are a lot of different kinds of heat recovery unit. One of it is applied in air
handling unit of X-building.
This thesis work consists of three main parts: theoretical research, measurements of
parameters of the air handling unit (AHU) in X-building and calculation of existing
heat recovery system as well as other type of heat recovery.
In theoretical part reader can familiarize with a review about main parts of ventilation
systems, which exactly handle the air and make it up. Some processes of air
conditioning are described. This part is necessary for understanding how different
types of heat recovery units work and what kind of equipment is better to use in some
special cases.
In next part of this thesis it is possible to find out information about measurements,
which were made during the work. It is also described in this part how much results of
3
3
measurements are different from data given by automation of air handling unit of X-
building. Certainly all reasons of differs are explained.
The last part of my thesis work is about calculations. All calculations are necessary to
get the values of annual energy efficiency. After all explanations two examples are
described: existing heat recovery applied in X-building and alternative type of heat
recovery as well. And finally it was found out what kind of these two systems is more
efficient
.
4
4
2. THEORETICAL BACKGROUND
To rich certain air conditions for supply air specialists use different kinds of air
handling units. There are often several ways to get required temperature and humidity.
It is also in common to use special devices for energy saving. All these points are
described in following paragraphs.
2.1 Air filters
Nowadays indoor air quality (IAQ) means a lot and there is a lot of attention paid for
this criteria. One of the most important things of IAQ is cleanliness of supply air. That
is why most of ventilation systems are equipped with air filters. There is also other
reason to install air filters in the system: to minimize risk of break moveable parts of
system like fans or heat recovery units due to dust, small leaves etc. /1 p.372./
There are some different types of air filters used in ventilation systems: bag or pocket
filters, pad filters, panel filters, roll filters, particulate air filters etc. Every kind of
filters has a range of size of particles, which are removed by this equipment. It is also
possible to use one-stage or several-stage cleaning. Obviously several-stage cleaning
provides better purification, but bigger operation and investment costs as well. It is
usual to have several stage air filtering. Every next stage’s filter removes less size
particles comparing with previous one. There are three stages defined:
primary stage filters remove majority of particles with size of 5-10 μm;
next stage filters provide cleanliness from particles of 0,5-5 μm size;
last stage is provided with low air velocity high efficiency particulate air
HEPA-filters./1 p.372./
Special electrostatic equipment could be also used to remove low-size dust from the
air stream. It is possible to use it effectively with much higher air velocity comparing
with HEPA-filters. /1 p. 373./
But if we are talking about energy efficiency of air handling unit it is necessary to
mention about pressure drop of air during the way through the filters. Higher pressure
drop means more energy needed to blow air through the system. And according to
5
5
ASHRAE 52.2 classification, which is described in table 1, high efficiency filters have
high value of pressure drop. That is why to provide good IAQ more energy is needed.
Table 1. ASHRAE 52.2 classification of filters / 1 p.374./
2.2 Fans
Fans are one of the main parts of every mechanical ventilation system. It is the very
device which blows air through the whole system. There are five types of fans which
are mostly used in ventilation systems:
axial flow;
centrifugal flow;
mixed flow;
tangential flow;
ring shaped. /2 p. 22./
All these types of fans are described on figure 1.
6
6
Figure 1. Types of fans /2 p. 22./
However in application to air handling units first three types are mostly in use. That is
why more attention will be paid to them in the next paragraphs.
2.2.1 Axial flow
Axial flow is one of the most used in ventilation. It is common to install axial flow
fans on round duct because of shape. This kind of fan mainly consists of two parts:
impeller and electrical motor. Impeller may have different number and shape of
blades. Mostly this amount is from 3 up to 12 blades. Figure 2 describes that blades
are turned that way to push air stream in direction, which parallel to the axis of
impeller’s spinning. This kind of fan is cheap to produce, moreover it has great
efficiency up to 85%, if it is equipped with special cylindrical case around the
impeller. /11 p. 22, 26-30./
Figure 2. Impeller of axial flow fan / 3./
7
7
2.2.2 Centrifugal or radial flow
This kind of fans is mostly used in systems with high pressure drop, because special
construction of impeller, which provides very high pressure. Special characteristics of
radial flow fan depend on impeller and blades shape. It may be bent backward,
forward, may be straightly radial or straight tilted backwards.
Bent backwards type of impeller makes centrifugal fans very efficient (up to 80%) at the low
noise level, however it is not recommended to use it with dirty air. It is mostly in common to
use straight blades tilted backwards to blow dirty air. Maximum efficiency of this kind of
equipment is 70%. Straightly radial blades reduce collecting dust and dirt on the impeller, it
reduces maintenance cost, but its efficiency is about 55%. And last type of impeller with
blades bended forwards makes possible to reduce size of fan and motor. Efficiency of this
kind of fan is up to 60%. /3./
Figure 3. Impeller shape for centrifugal fan / 3./
2.2.3 Mixed flow
This kind of impeller combines principle of work of both axial and centrifugal flow
fans. Impeller with blades is described on figure 4. Blades with angle of 45 degrees
increase static pressure due to centrifugal force. Efficiency of mixed flow fans is up to
80%.
8
8
Figure 4. Impeller of mixed flow fan / 3./
2.3 Heating coils
This type of equipment is used to warm up air from outdoor in cold seasons.
Nowadays heat for heating coil could be gotten by means of electricity, hot water and
steam.
Electrical heating coils, which are shown on figure 5, are mostly connected to
3/380V/50 Hz electrical network. This type of construction makes it easier to uninstall
or repair coil. This type of coil is also equipped by safety thermostat, which prevents
excessive heating of the system and switch coil of in case of air flow stops. /4 p.188./
Figure 5. Electrical heater / 5./
Effective area of hot water heating coils described on figure 6 mainly made of copper
because of its perfect thermal conductivity. It consists of tubes with aluminum fins,
9
9
which increase heating effect by increasing usable area. This type of coil is also
equipped by safety devices to prevent accidents. /4 p.188./
Figure 6. Hot water heater / 5./
It is also common to use in steam as a medium heating coils. This way of air heating is
very useful because of two steps of heating: directly by heat of steam and also by heat
emitted by condensation of steam.
Choice of heaters type depends on the client’s desires and circumstances. For
example, if client is limited of electrical power the only way is to use hot water
heating coil. The heating process is clearly seen in id-diagram in figure 7.
Figure 7. Electrical and hot water heating coil
10
10
It is obvious according to figure 7 that heating coils do not change moisture content.
2.4 Cooling coils
Cooling coils could use gases, water-glycol mixture and water as a refrigerant.
Designer often makes projects with two steps of air cooling. First one is precooling
and it reduces loads on the cooling equipment. This step may be provided by cold
water cooling coil. Second one is properly cooling with resort to refrigerating
equipment. There are two ways of cooling process: with and without condensation. /4
p.187./
If evaporation of refrigerant occurs in cooling coil, it is considered that temperature of
cooling surface is constant. That is why there is no condensation from the air in the
cooling coil and moisture content is constant as well. This process is shown on figure
8. /4 p.187./
There is other kind of cooling coils with cooling surface with constant temperature
under the dew point. Figure 9 describes this process. In this case condensation occurs,
that’s why moisture content of air reduces. /1 p.187./
11
11
Figure 8. Cooling without condensation Figure 9. Cooling with condensation
2.5 Humidifiers
There are two types of humidifiers, which are mostly used in AHU. Principle of their
operation is different. The first one humidifies air by spraying cold water to keep fog
conditions in humidifier. Air adiabatically absorbs moisture from fog by going
through it, what is clearly shown on figure 10. This kind of equipment costs less
comparing with another, but hygienic risks are very high, therefore it is common to
use steam humidifiers. This kind of equipment has some advantages:
-dry steam could be easily and quickly mixed with air
-dry steam does not contain any microorganisms and minerals
-low cost maintaining of this system. /4 p.188-189./
12
12
Figure 10. Cold water humidifier Figure 11. Steam humidifier
2.6 Dehumidifiers
In some regions there is a great likelihood of high humidity of outdoor air. So
sometimes it is necessary to dehumidify air. Different ways can be chosen to reach
certain level of humidity. HVAC designers usually use cooling-dehumidifying coils,
which mostly the same as cooling coil with condensation shown on figure 9. In some
cases chemical compounds can be also used to absorb moisture from the air. /3./
2.7 Energy recovery ventilation systems
These systems are used to reduce operation costs for ventilation by exchanging
sensible and latent heat from exhausted air to outdoor air. There are two types of these
systems:
-heat recovery ventilators (HRV),
13
13
-energy recovery ventilators (ERV).
Heat recovery ventilators transfer sensible heat only, what is described on figures 12
and 13. HRV systems are subdivided on different types: plate heat recovery, water-
glycol double coil system, heat pipe heat exchanger, two-phase thermosiphon heat
exchanger. Plate heat recovery and double coil system are more common in use
comparing with last two. /2 p. 11-18./
Figure 12. HRV without condensation Figure 13. HRV with condensation
2.7.1 Heat recovery ventilators
2.7.1.1 Plate heat recovery
Operation principle of this system is pretty simple. Figure 14 simply shows it. This
equipment consists of only stationary parts. It has a lot of layers separated from each
other by plates.
14
14
Figure 14. Cross-flow plate heat recovery/ 7./
For winter case as example: cold outdoor supply air (3) comes between plates and
warmed up (2) straightly by heat transferred from warm exhaust air (1) by plates.
Warm exhaust air is cooled down during this process and blown out as cold exhaust
air (4). Sometimes it is very useful to put few cross-sections one after another to
improve efficiency. Because of small cross-leakage (0 to 5%) value it is possible to
use as exhaust wasted air, for example, from WC’s, according to Finnish National
Building Codes D2. But in special buildings for example in hospitals any cross-
leakages are totally restricted, so it is impossible to use plate heat recovery in these
cases. /8 p.11-13./
The advantages are lack of moving parts, low pressure drop (5 to 450 Pa) and
simplicity of cleaning. All these points make low operation cost for plate heat
recovery. Efficiency of plate heat recovery is from 50% up to 80%, depends on plates
spacing and construction. /8 p.12./
2.7.1.2 Double coil heat recovery
This kind of system is very common in use for special buildings like hospitals, where
any cross-leakages are restricted. It compensates rather small efficiency (45 to 60%)
comparing thermal weal and plate heat recovery.
15
15
Operation principle of double coil system is shown on Figure 15. There are two heat
exchangers for supply and exhaust air ducts. These coils are connected with each other
by pipes. Water or other liquid is pumped over heat exchangers. For winter case media
gets heat from exhaust air and goes to supply air coil, where it warm up outdoor air.
Figure 15. Double-coil heat recovery /8 p.15./
Efficiency of this system is regulated by three-pot valve controlled by two sensors.
This valve is also used to prevent freezing of moisture in exhaust air coil. Usually
ethylene glycol is added in water to prevent freezing of media in supply air heat
exchanger. Expansion tank is necessary to allow media to contract and expand. /8
p.15./
Double coil system allows to separate exhaust duct from supply. It could be very
useful in case of limited space or in case of necessity to make it separate. This solution
is applied for example in Central Hospital of Mikkeli.
2.7.1.3 Heat pipe heat recovery
16
16
Heat pipe heat recovery looks like ordinary water coil, except for tubes separated from
each other. This kind of heat recovery unit has two sides: evaporation side and
condensing side. There is partition wall between these parts. It narrows cross leakage
down to 0% (if pressure difference between two parts less than 12 kPa). /8 p.16./
Figure 16. Heat pipe heat recovery/8 p.16./
Main principle of operation (Figure 17) is as cooling machine. Hot air goes through
the evaporation part and evaporation of working fluid occurs. Vapor goes up in
condensing part of exchanger, through which cold air goes. In this side vapor cools
down and flows in the bottom of heat pipe to evaporation side. When fluid vaporizes,
it takes a lot of energy from the air stream by its cooling. During the condensation of
fluid emitting of heat occurs. Cold air gets warmer by passing through condensation
side./2 p.16./
Figure 17. Heat pipe/8 p.16./
17
17
Affective area made of copper or aluminum as well due to good thermal conductivity.
To improve the efficiency heat pipes covered with fins. Fins usually made of the same
material as heat pipes to avoid problems with different thermal expansion. Spacing
between fins depends on application of this heat recovery unit. For ventilation it is
common to use spacing of 1.8 to 2.3 mm. /8 p.16-17./
Efficiency of heat pipe heat recovery is in linear dependence on number of rows of
heat pipes. For example: in case of 7 rows efficiency is 66%, but heat exchanger with
14 rows of heat pipes has 83% efficiency with the same mass flow, face velocity 2 m/s
and same fin spacing 1.8 mm. Efficiency is also depends on inside diameter of heat
pipes. For instance heat transfer increases squarely if it is used heat pipes with inside
diameter 25 mm instead of 16 mm. But increasing number of rows and diameter of
heat pipes draws big values of pressure drop on heat exchanger and more powerful fan
is needed. /8 p.17./
During the operation effectiveness is changed by changing the slope to the horizontal.
Value of this slope is regulated by tilt controller, which works automatically. Because
of changing the slope there is a necessity of flexible connections with ducts. It is
obvious that heat pipe heat exchanger may operate in both directions: in summer and
winter as well. Direction of operation could be also changed by tilt controller. /8 p.
17./
2.7.2 Enthalpy recovery ventilators
ERV recover sensible and latent heat as well (Figure 18). There are two types of ERV:
rotating wheel heat recovery and special kind of plate heat recovery. Enthalpy wheel
is one of the most common in use heat recovery units. It is used for example in X-
building.
18
18
Figure 18. Energy recovery ventilator
But ERV’s have one important disadvantage – big value of cross-leakages (up to
10%). That’s why using of ERVs is limited by cleanliness of exhaust air. According to
National Building Code D2 it is restricted to use air from waste spaces (WC’s for
example) as exhaust air. So volume flow of supply air is bigger than volume flow of
exhaust air. Because of this inequality efficiency of enthalpy wheel is much less than
announced by manufacturer. /8 p.12-13./
2.7.2.1 Rotating wheel heat recovery
Figure 19 describes construction of the Rotating wheel heat recovery unit. It consists
of three main parts: frame made of steel, rotating wheel and electrical motor with belt-
transmission. Wheel is made of aluminum and composed of big amount of cells or
meshed wire. These constructions allow to increase operating area and therefore
effectiveness (up to 90% with equal volume flows of both supply and exhaust air
streams). /9./
19
19
Figure 19. Rotating wheel heat recovery/8 p.13./
There are three types of rotating wheel heat recovery:
RRS, RRT – common model, which is used to utilize sensible heat from warm
air stream. Wheels of RRT-type transfer moisture only in cases when
temperature of cold air stream is under the dew point. Thermal wheel is made
of aluminum, which is resistant with salt water.
RRH – high temperature thermal wheels, which are used to transfer sensible
heat from air with temperature of 250°С
RRSE, RRTE – enthalpy wheels, which are used to utilize total heat (sensible
and latent heat as well). /9./
2.7.2.2 Permeable membrane plate heat recovery
This kind of ERV is mostly the same as normal plate heat recovery except one thing –
the plates, which separate air streams from each other, are made of materials are
permeable by moisture. It is common to use some polymers and cellulose to make
membranes. Construction and composition of these heat and moisture exchangers are
20
20
developed that way to minimize cross-leakage and prevent any air transfer through the
plates. /8 p.12./
21
21
3. MEASUREMENTS AND COMPAIRING
The main point of following paragraph is to describe methods of measuring applied
during this thesis work and to compare results of measurements with values which are
given by automation system of air handling unit of X-building.
3.1 Measurements made by data loggers
To get value of energy efficiency of heat recovery it is absolutely necessary to
measure temperatures before and after recuperator for both supply and exhaust air
streams. Also the values of supply air temperature are also needed. That is why there
are five points where data loggers were installed. All points are shown black on figure
20. One logger should be put after fan for supply air because of small rise of the
temperature, but due to impossibility of installing logger on that place, it was put just
before fan. This figure was screen-shouted from special program, which monitors and
controls and collects all characteristic points of the system. It is possible to get values
of temperature or humidity of air, energy consumption of fans, volume flow etc. After
month ends, all data of each hour exports to special document.
22
22
Figure 20. Loggers location in the air handling unit of X-building
There is a table in appendix 1, where data from loggers and AHU-automation are
compared. Last four columns describe difference between values from different
sources. According to this table most values of divergence are less than two degrees,
but the biggest divergence is 4,8 degrees of Celsius, which is really huge. It can be
explained by location of loggers in the AHU. Because of high volume flow, ducts with
high dimensions are needed (cross section is more than one square meter). To get
really adequate values it is necessary to have several points of measuring. It was
impossible to put 25 to each of five points due to technical reasons. Moreover most of
loggers were placed near the wall of duct because the only place to fix it safely is near
the wall.
3.2 Measuring of volume flow from WCs
Other point to measure was volume flow of air going from WCs straightly to the roof.
Due to zero-efficiency this value has great influence on the annual energy efficiency
for whole ventilation system. It was decided that the easiest available method to make
this kind of measurements is to measure velocity of air stream in the duct.
Because of this system was new some preparations were needed. Firstly it was
necessary to make a small opening to make possible to put sensor inside of duct. Next
thing to do was to measure diameter of the duct, as a result of 315 mm was gotten.
Usually air velocity is measured by five-point method for this duct size. Cross section
of duct with points of measuring are shown schematically on figure 21.
23
23
Figure 21. Cross section of duct with points of measuring
“Swema ” measuring instrument equipped with hot wire sensor was used. After all
preparation processes air velocity was measured. But fluctuations of values given by
anemometer were quite big ( ). However according to measurements
average velocity of air stream in the duct is 3,57 m/s. It is easy to find out value of
volume flow:
(1)
where is velocity of air stream, is internal diameter of the duct. As a result volume
flow of 0,278 was gotten. According to data from automation system of AHU in
X-building, difference between supply and exhaust air volume flows is about 0,32
. But this value is not exactly for moment of measuring, so it is quite difficult to
judge if measuring results are true or not.
As a result for this paragraph it becomes obvious that incompleteness of measuring
provided with results, which are not exactly right. Moreover air handling unit was
designed the best way to make monitoring and control of system perfect by providing
objective and trough values like temperature, humidity, volume flow of air, energy
consumption etc. So it is better to use values given by automation of system to make
following calculations.
24
24
4. CALCULATIONS AND COMPARING
Main idea of this paragraph is to familiarize reader with process of calculating annual
energy efficiency. This value is very important and may be it can determine choice of
customer what kind of heat recovery is better to use in air handling unit.
4.1 Order and description of calculations
First of all, it is necessary to calculate temperature ratio of existing air handling unit
from data loggers. It can be easily calculated by formula 2. Only point to remember is
to use in this formula data for outdoor temperatures between -5°C and +17°C.
According to data temperature ratio for supply air is about 76%. But in following
calculations it is necessary to know value of temperature ratio for equal volume flows,
so in our case this value is 84%.
(2)
Annual energy efficiency can be calculated by creating table, which is shown in
appendix 2 and 3. A lot of different values are necessary for that. Firstly duration
curve is needed. Example of duration curve is shown on figure 19. It is a graph which
describes how much time (given in axis of abscissas in percent from whole year)
outside temperature is below given one (given in axis of ordinate in degrees of
Celsius). Table form of duration curve is more useful to our purposes.
25
25
Figure 19. Duration curve
Calculation of the table begins from getting ratio between supply air volume flow and
exhaust air volume flow.
(3)
According to requirements must be more than 1 for energy recovery ventilators.
This is exactly case of HRV for X-building, because rotating weal heat recovery is
used in that AHU. Real temperature ratios for HR in cases like this are different from
values which given by manufacturer, however it can be calculated by following
formulas:
(4)
(5)
26
26
where is value of temperature ratio given by manufacturer, is temperature ratio
of supply air for actual value of , is temperature ratio for exhaust air for
actual value of .
Next point to calculate is temperature of exhaust air:
(6)
where is temperature of indoor air, is outdoor air temperature.
But according to National Building Codes of Finland exhaust air temperature must not
be less than 5°C due to risk of frozen in heat recovery ventilator. Indoor air
temperature must be in range of +21°C +23°C to meet requirements of D2, but
it is in common to use in calculations value of +21°C. Because of these points
actual temperature ratios must be reduced:
(7)
(8)
where is an actual temperature ratio for exhaust air, is actual
temperature ratio for supply air, is temperature of exhaust air (not less
than +5°C)./ 10./
Next step is to get value of actual temperature of supply air after heat recovery. It can
be easily calculated by formula:
(9)
But must not be more than +17°C because of providing indoor air
temperature +21°C during the hot season. This is another reason to reduce efficiency
of heat recovery ventilator.
One of the last points to calculate is heat recovery energy.
(10)
Where is a specific heat capacity, is duration of certain outdoor temperature in
hours, dencity of the air, is operation time during the day, is operation days
during the week.
27
27
and values were defined from schedule of AHU, given by automation.
Also it is necessary to find out value of energy needed for ventilation:
(11)
It is needed to make all these calculations for each outdoor temperature (from -35°C
up to +28°C). It is easier to collect all that information in table. After that sum of heat
recovery energy and separately energy for ventilation is needed.
Finally it becomes possible to get annual energy efficiency of AHU:
(12)
Where is a sum of heat recovery energy for all outdoor temperatures,
is sum of energy needed for ventilation.
Firstly it was necessary to get this value for existing system. Because now rotating
weal is used there are different air flows. In X-building special exhaust system for
WCs was created. It is obvious that efficiency of this special system is =0%. This
factor must be noticed in calculations: it is also calculated for each outdoor
temperature with volume flow which was measured in the duct from WCs. Because of
permanent work of WCs fan, = =1.
Value of annual energy efficiency of AHU is not enough to full comparing, so value
of total annual energy efficiency of whole ventilation system of building. To get this
value it is necessary to calculate according to formula 13:
(13)
where is an energy recovered from ventilation can be estimated using the
equation 14, is net heating energy for ventilation could be found by formula 15,
is heating power of supply air in a space was calculated by equation 16,
is power needed for heating of make-up air in a space.
(14)
(15)
28
28
(16)
(17)
where is mean outdoor air temperature during month (given in D5), is
temperature of inblown air, , is make-up air volume flow, is supply
air temperature after HR could be calculated using formula 19.
(18)
(19)
where is indoor air temperature. /11 p.19-21./
4.2 Comparing of existing HRU with alternative
Counter-flow plate heat recovery with announced temperature ratio of 70% was
found. Exactly this value is recommended to use in calculations according to National
Building Code of Finland D5. It is also useful to compare results with values of cross-
flow HR with temperature ratio of 55% according to D5. /11 p.20/
It is allowed to blow exhaust air from WCs through heat recovery. In spite of lower
temperature ratio comparing with rotating weal energy recovery plate heat recovery
can have better annual energy efficiency due to equal volume flows for both supply
and exhaust air streams. But there is a factor, which reduces total efficiency: building
must have some ventilation during night time and weekends. In calculations value
equal existing volume flow from WCs is used.
One of the main point to define in this thesis work is to find out what kind of system
has better annual energy efficiency existing rotating weal with =1,11 or plate heat
recovery with =1. Other point to mention is that according to D5 National
Building Code of Finland minimum temperature of exhaust air must be limited by
0°C.
29
29
All calculations shown in application 2, 3, 4, 5, 6, 7 for both of these systems were
made according formulas 3 - 19. Results are close to each other, but using plate heat
recovery has a bit bigger value of annual energy efficiency of whole ventilation
system (63.4% - for counter-flow plate heat recovery, 52.8% - for cross-flow plate
heat recovery, 55.3% - for rotating weal heat recovery).
Moreover less investment for ducting and additional fan needed in case of plate heat
recovery. But it also has some disadvantages, and one of the most important from
them is risk of cross leakages. In spite of permission of requirement documentation it
can cause some problem. It can be solved by keeping certain pressure drop in the
system special way to provide cross leakage going from supply air stream to exhaust
and to prevent it in opposite direction.
30
30
5. CONCLUSION
First part of this thesis mostly consists of information about different parts of air
handling units. There are the most important processes, which take place in air
handling, described there. That information was mentioned to make it easier to
understand next paragraphs for non-specialized at HVAC-systems reader.
Next part is about measurements with results, calculations and comparing. It was
necessary to make some measurements to calculate annual energy efficiency of the
existing air handling unit. There some documents were used to base calculations of
energy efficiency for other types of heat recovery units.
So as a result of this thesis work it is possible to say that designers of air handling unit
in X-building had some alternative ways to reach efficient way of energy usage. Their
choice was applying rotating weal heat recovery in the system. As an alternative way
case of cross flow heat recovery was calculated. Both of these two variants have more
or less the same results, however the second type has bigger value of annual energy
efficiency. But designers chose more healthy and safety way. .
31
31
BIBLIOGRAPHY
1. Sutherland Ken. Filters and filtration handbook. UK. Elsevier. 2008
2. Cory William. Fans and ventilation. UK. Elsevier. 2005
3. Типы вентиляторов. NorrisVent. WWW document. Refered 17.03.2012. Update time not
available.
http://www.norrisvent.ru/ShowNodeNID25.html
4. Ананьев В.А.. Системы вентиляции и кондиционирования. Теория и практика. Россия.
Евроклимат. 2003
5. Air heaters. Vents. WWW document. http-//www.ventilation-system.com/cat/72/. Referred
14.12.2011. Update time not available.
6. Dehumidifying. ENGINEERINGTOOLBOX. WWW document.
http://www.engineeringtoolbox.com/cooling-dehumidifying-air-d_695.html. Referred
17.03.2012
7. Вентиляторы. Klimatvrn. WWW document. Referred 17.03.2012.Update time not available.
http://www.klimatvrn.ru/page/page60
8. ASHRAE HANDBOOK. HVAC systems and equipment. Chapter 44. 2000
9. Вращающиеся рекуператоры. Rozenberg. WWW document.
http://www.rosenberg.ru/equipment/rotor-rec.php. Referred 17.03.2012
10. D2 National Building Code of Finland
11. D5 National Building Code of Finland. Draft 28.09.2010.
32
32
Appendix 1. Data comparision
Date/Time
loggers AHU-automation difference
tout ttLTO ts tpLTO tout ttLTO ts tpLTO tout ttLTO ts tpLTO
°C °C °C °C °C °C °C °C °C °C °C °C
2.12.2011 9:00:00 4 17 21,2 9,4 2,99 15,3 21,02 7,76 -1,01 -1,7 -0,18 -1,64
2.12.2011 10:00:00 4,3 17,1 21,4 9,8 3,53 15,4 21,12 8,05 -0,77 -1,7 -0,28 -1,75
2.12.2011 11:00:00 4,3 17,1 21,4 9,7 3,98 15,6 21,18 8,22 -0,32 -1,5 -0,22 -1,48
2.12.2011 12:00:00 4,5 17,1 21,4 9,8 3,98 15,6 21,18 8,3 -0,52 -1,5 -0,22 -1,5
2.12.2011 13:00:00 4,4 17,1 21,4 9,8 3,98 15,6 21,13 8,3 -0,42 -1,5 -0,27 -1,5
2.12.2011 14:00:00 4,2 17,1 21,4 9,7 3,98 15,6 21,17 8,13 -0,22 -1,6 -0,23 -1,57
2.12.2011 15:00:00 4,1 17 21,4 9,6 3,88 15,5 21,15 8,09 -0,22 -1,5 -0,25 -1,51
2.12.2011 16:00:00 4,2 16,8 21,1 9,6 3,69 15,4 21,05 8 -0,51 -1,4 -0,05 -1,6
2.12.2011 17:00:00 3,8 16,7 21 9,3 3,68 15,3 20,9 7,86 -0,12 -1,4 -0,1 -1,44
2.12.2011 18:00:00 4,1 16,8 21,1 9,4 3,69 15,3 20,84 7,82 -0,41 -1,5 -0,26 -1,58
2.12.2011 19:00:00 3,7 17 21,1 8,8 3,69 15,5 20,85 7,46 -0,01 -1,5 -0,25 -1,34
2.12.2011 20:00:00 3,5 17 21,1 8,6 3,69 15,5 20,91 7,28 0,19 -1,5 -0,19 -1,32
2.12.2011 21:00:00 3 21,1 17,7 13,5 3,4 18,5 20,03 11,4 0,4 -2,6 2,33 -2,08
2.12.2011 22:00:00 2,4 20,9 17,7 15,2 2,87 19,1 19,57 14,4 0,47 -1,8 1,87 -0,83
2.12.2011 23:00:00 2,1 20,8 17,9 15,9 2,83 19,3 19,53 15,3 0,73 -1,5 1,63 -0,64
3.12.2011 1,9 20,9 18,1 16,2 2,16 19,6 19,53 15,7 0,26 -1,3 1,43 -0,55
3.12.2011 1:00:00 1,6 21 18,2 16,5 1,81 19,8 19,53 15,9 0,21 -1,2 1,33 -0,57
3.12.2011 2:00:00 1,2 21,2 18,4 16,6 0,9 20 19,52 16 -0,3 -1,2 1,12 -0,59
3.12.2011 3:00:00 1,1 21,4 18,5 16,7 0,39 20,2 19,54 16,2 -0,71 -1,3 1,04 -0,53
3.12.2011 4:00:00 1,1 21,5 18,6 16,8 0,39 20,3 19,56 16,3 -0,71 -1,2 0,96 -0,54
3.12.2011 5:00:00 1,1 21,6 18,7 17 0,39 20,4 19,67 16,4 -0,71 -1,2 0,97 -0,6
3.12.2011 6:00:00 1,1 21,7 18,8 17,1 0,39 20,6 19,69 16,5 -0,71 -1,2 0,89 -0,58
3.12.2011 7:00:00 1,6 21,8 19 17,3 0,78 20,7 19,71 16,7 -0,82 -1,1 0,71 -0,62
3.12.2011 8:00:00 1,9 22 19,2 17,5 0,91 20,8 19,77 16,9 -0,99 -1,2 0,57 -0,58
3.12.2011 9:00:00 1,8 22,1 19,2 17,7 1,08 20,9 19,7 17 -0,72 -1,2 0,5 -0,7
3.12.2011 10:00:00 1,7 22,1 19,3 17,7 1,25 20,9 19,53 17,1 -0,45 -1,2 0,23 -0,6
3.12.2011 11:00:00 1,6 22,1 19,3 17,7 1,24 20,9 19,36 17,1 -0,36 -1,2 0,06 -0,61
3.12.2011 12:00:00 1,9 22,1 19,2 17,7 1,25 20,8 19,27 17 -0,65 -1,3 0,07 -0,68
3.12.2011 13:00:00 1,8 22,1 19,2 17,6 1,25 20,8 19,27 17 -0,55 -1,3 0,07 -0,63
3.12.2011 14:00:00 1,3 22,1 19,2 17,6 1,09 20,8 19,28 17 -0,21 -1,3 0,08 -0,64
3.12.2011 15:00:00 0,4 22 19,1 17,4 0,53 20,8 19,26 16,8 0,13 -1,2 0,16 -0,61
3.12.2011 16:00:00 -0,3 22,1 19 17,4 -0,59 20,8 19,28 16,8 -0,29 -1,3 0,28 -0,6
3.12.2011 17:00:00 -0,9 22 18,9 17,1 -1,13 20,8 19,42 16,6 -0,23 -1,2 0,52 -0,51
3.12.2011 18:00:00 -1,5 22,1 19 17,2 -1,32 20,8 19,45 16,6 0,18 -1,3 0,45 -0,63
3.12.2011 19:00:00 -1,5 22,1 19 17,3 -1,61 20,8 19,57 16,7 -0,11 -1,3 0,57 -0,59
3.12.2011 20:00:00 -0,8 22,1 19,1 17,5 -2,06 20,9 19,65 16,9 -1,26 -1,3 0,55 -0,65
3.12.2011 21:00:00 -0,2 22,2 19,2 17,7 -1,48 20,9 19,71 17 -1,28 -1,3 0,51 -0,7
3.12.2011 22:00:00 1,1 22,3 19,3 17,8 -0,69 21 19,81 17,2 -1,79 -1,3 0,51 -0,63
3.12.2011 23:00:00 1,6 22,3 19,3 17,9 0,33 21 19,87 17,3 -1,27 -1,3 0,57 -0,56
4.12.2011 1,9 22,4 19,4 18,1 0,8 21,1 19,88 17,5 -1,1 -1,3 0,48 -0,64
4.12.2011 1:00:00 2,4 22,4 19,5 18,2 1,1 21,2 19,9 17,6 -1,3 -1,2 0,4 -0,64
33
33
4.12.2011 2:00:00 2,4 22,5 19,5 18,3 1,32 21,2 19,92 17,7 -1,08 -1,3 0,42 -0,64
4.12.2011 3:00:00 2,2 22,5 19,7 18,5 1,72 21,3 19,93 17,8 -0,48 -1,2 0,23 -0,71
4.12.2011 4:00:00 2,1 22,6 19,7 18,5 1,72 21,4 19,94 17,9 -0,38 -1,3 0,24 -0,65
4.12.2011 5:00:00 1,9 22,6 19,8 18,6 1,72 21,4 19,92 17,9 -0,18 -1,2 0,12 -0,66
4.12.2011 6:00:00 1,7 22,7 19,8 18,6 1,72 21,4 19,99 18 0,02 -1,3 0,19 -0,57
4.12.2011 7:00:00 1,4 22,7 19,9 18,7 1,72 21,5 20,03 18 0,32 -1,2 0,13 -0,66
4.12.2011 8:00:00 1 22,7 19,9 18,6 1,63 21,5 20,01 18 0,63 -1,2 0,11 -0,58
4.12.2011 9:00:00 0,9 22,7 19,9 18,5 1,2 21,5 20,02 17,9 0,3 -1,2 0,12 -0,61
4.12.2011 10:00:00 1,1 22,7 19,9 18,4 1,2 21,5 20,03 17,8 0,1 -1,2 0,13 -0,62
4.12.2011 11:00:00 1,4 22,7 19,8 18,2 1,2 21,5 20,02 17,7 -0,2 -1,2 0,22 -0,51
4.12.2011 12:00:00 1,5 22,7 19,8 18,2 1,2 21,5 20,02 17,7 -0,3 -1,2 0,22 -0,54
4.12.2011 13:00:00 1,2 22,7 19,7 18,1 1,43 21,5 19,99 17,6 0,23 -1,2 0,29 -0,52
4.12.2011 14:00:00 1,9 22,7 19,5 17,9 1,55 21,5 19,92 17,4 -0,35 -1,2 0,42 -0,54
4.12.2011 15:00:00 2,2 22,7 19,5 17,8 1,53 21,4 19,91 17,3 -0,67 -1,3 0,41 -0,55
4.12.2011 16:00:00 2,8 22,7 19,4 17,7 1,89 21,4 19,91 17,1 -0,91 -1,3 0,51 -0,63
4.12.2011 17:00:00 3 22,7 19,4 17,5 2,08 21,4 19,94 17 -0,92 -1,3 0,54 -0,54
4.12.2011 18:00:00 3 22,7 19,4 17,9 2,11 21,4 20 17,2 -0,89 -1,3 0,6 -0,7
4.12.2011 19:00:00 2,7 22,7 19,5 18 2,35 21,5 20,01 17,4 -0,35 -1,2 0,51 -0,59
4.12.2011 20:00:00 2,6 22,7 19,7 18,1 2,43 21,5 20,03 17,5 -0,17 -1,2 0,33 -0,56
4.12.2011 21:00:00 2,2 22,7 19,7 18,2 2,38 21,5 20,03 17,6 0,18 -1,2 0,33 -0,62
4.12.2011 22:00:00 1,7 22,8 19,7 18,1 1,61 21,6 20,02 17,6 -0,09 -1,3 0,32 -0,52
4.12.2011 23:00:00 1,9 22,8 19,8 18,2 1,22 21,5 20,03 17,6 -0,68 -1,3 0,23 -0,62
5.12.2011 2,1 22,8 19,8 18,2 1,29 21,6 20,03 17,7 -0,81 -1,2 0,23 -0,55
5.12.2011 1:00:00 1,2 22,8 19,8 18,2 1,81 21,6 20,12 17,7 0,61 -1,2 0,32 -0,49
5.12.2011 2:00:00 1,6 22,8 19,9 18,4 0,86 21,6 20,15 17,7 -0,74 -1,2 0,25 -0,67
5.12.2011 3:00:00 1,8 23 19,9 18,5 1,24 21,7 20,16 17,8 -0,56 -1,3 0,26 -0,7
5.12.2011 4:00:00 1,8 23 19,9 18,4 1,27 21,7 20,15 17,8 -0,53 -1,3 0,25 -0,58
5.12.2011 5:00:00 1,8 23 19,9 18,4 1,27 21,7 20,18 17,7 -0,53 -1,4 0,28 -0,68
5.12.2011 6:00:00 1,7 23 19,9 18,4 1,27 21,7 20,21 17,7 -0,43 -1,3 0,31 -0,67
5.12.2011 7:00:00 1,5 23 19,9 18,4 1,27 21,7 20,2 17,7 -0,23 -1,3 0,3 -0,68
5.12.2011 8:00:00 0,8 16,4 21,4 7,5 1,24 15,5 21,15 7,01 0,44 -0,9 -0,25 -0,49
5.12.2011 9:00:00 0 16,2 21,5 6,9 0,51 14,4 21,29 5,4 0,51 -1,8 -0,21 -1,5
5.12.2011 10:00:00 -0,2 16,2 21,5 6,6 -0,17 14,2 21,42 5,01 0,03 -2 -0,08 -1,59
5.12.2011 11:00:00 0,5 16,4 21,6 7,3 -0,28 14,4 21,55 5,29 -0,78 -2,1 -0,05 -2,01
5.12.2011 12:00:00 0,3 16,1 21,4 7,1 -0,28 14,3 21,31 5,45 -0,58 -1,8 -0,09 -1,65
5.12.2011 13:00:00 0,2 16 21,2 6,9 -0,01 14,2 21,19 5,32 -0,21 -1,8 -0,01 -1,58
5.12.2011 14:00:00 0,3 16 21,2 7 0,13 14,1 21,11 5,22 -0,17 -1,9 -0,09 -1,78
5.12.2011 15:00:00 0,7 16,1 21,2 7,3 0,18 14,2 21,14 5,38 -0,52 -2 -0,06 -1,92
5.12.2011 16:00:00 0,7 16 21,1 7,1 0,43 14,2 21,11 5,57 -0,27 -1,8 0,01 -1,53
5.12.2011 17:00:00 0,6 15,9 21 7,1 0,24 14,1 20,99 5,39 -0,36 -1,8 -0,01 -1,71
5.12.2011 18:00:00 1,2 16 21 7,5 0,38 14,2 20,86 5,71 -0,82 -1,8 -0,14 -1,79
5.12.2011 19:00:00 1 16,5 21,1 6,9 0,44 14,5 20,82 5,36 -0,56 -2 -0,28 -1,54
5.12.2011 20:00:00 0,7 16,5 21,4 6,8 0,44 14,7 21,1 5,24 -0,26 -1,8 -0,3 -1,56
5.12.2011 21:00:00 1,1 24,2 17,1 12,4 0,44 20,1 20,32 9,91 -0,66 -4,1 3,22 -2,49
5.12.2011 22:00:00 0,8 22,8 17,5 14,4 0,44 20,4 19,95 13,5 -0,36 -2,4 2,45 -0,86
5.12.2011 23:00:00 0,5 22,1 17,9 15,3 0,44 20,2 19,95 14,8 -0,06 -2 2,05 -0,53
34
34
6.12.2011 -0,3 21,7 18,1 15,8 -0,1 20,1 19,94 15,3 0,2 -1,6 1,84 -0,55
6.12.2011 1:00:00 -0,2 21,6 18,4 16,2 -0,66 20,1 19,88 15,7 -0,46 -1,5 1,48 -0,54
6.12.2011 2:00:00 0,3 21,6 18,6 16,6 0,05 20,2 19,83 16 -0,25 -1,4 1,23 -0,61
6.12.2011 3:00:00 0,6 21,7 18,7 16,8 0,05 20,4 19,8 16,2 -0,55 -1,4 1,1 -0,6
6.12.2011 4:00:00 0,6 21,8 18,8 17,2 0,05 20,5 19,82 16,5 -0,55 -1,3 1,02 -0,66
6.12.2011 5:00:00 0,6 22 19,1 17,4 0,3 20,6 19,86 16,8 -0,3 -1,4 0,76 -0,59
6.12.2011 6:00:00 0,5 22,1 19,2 17,6 0,4 20,7 19,95 17 -0,1 -1,4 0,75 -0,58
6.12.2011 7:00:00 0,6 22,2 19,3 17,7 0,37 20,8 19,95 17,1 -0,23 -1,4 0,65 -0,62
6.12.2011 8:00:00 0,2 16,5 21,6 7,1 0,37 15,2 21,19 6,44 0,17 -1,3 -0,41 -0,66
6.12.2011 9:00:00 0,1 16,5 21,7 7 0,37 14,6 21,53 5,38 0,27 -2 -0,17 -1,62
6.12.2011 10:00:00 -0,1 16,4 21,7 6,9 0,37 14,5 21,54 5,3 0,47 -1,9 -0,16 -1,6
6.12.2011 11:00:00 0,2 16,5 21,7 7,1 0,37 14,5 21,53 5,32 0,17 -2 -0,17 -1,78
6.12.2011 12:00:00 0,3 16,5 21,7 7,2 0,37 14,6 21,51 5,48 0,07 -1,9 -0,19 -1,72
6.12.2011 13:00:00 0,2 16,4 21,6 7,1 0,37 14,6 21,5 5,48 0,17 -1,8 -0,1 -1,62
6.12.2011 14:00:00 0,1 16,4 21,6 7 0,37 14,4 21,42 5,39 0,27 -2 -0,18 -1,61
6.12.2011 15:00:00 0,1 16,2 21,6 7 0,37 14,4 21,4 5,32 0,27 -1,8 -0,2 -1,68
6.12.2011 16:00:00 -0,3 16,2 21,5 6,8 0,37 14,4 21,39 5,22 0,67 -1,8 -0,11 -1,58
6.12.2011 17:00:00 -0,5 16,1 21,5 6,6 0,37 14,3 21,38 5,1 0,87 -1,8 -0,12 -1,5
6.12.2011 18:00:00 -0,5 16 21,4 6,6 0,05 14,1 21,27 4,88 0,55 -1,9 -0,13 -1,72
6.12.2011 19:00:00 -0,2 16,2 21,2 6,1 0,05 14,3 21,09 4,48 0,25 -1,9 -0,11 -1,62
6.12.2011 20:00:00 0,1 16,4 21,2 6,4 0,01 14,4 21,12 4,73 -0,09 -2 -0,08 -1,67
6.12.2011 21:00:00 0,5 22,9 17,1 12,1 0 19,2 20,25 9,77 -0,5 -3,7 3,15 -2,33
6.12.2011 22:00:00 0 21,9 17,3 14,2 0 19,6 19,82 13,4 0 -2,3 2,52 -0,76
6.12.2011 23:00:00 -0,1 21,4 17,8 15,3 0 19,6 19,81 14,7 0,1 -1,9 2,01 -0,65
7.12.2011 -0,1 21,2 18,1 15,9 0 19,7 19,79 15,4 0,1 -1,5 1,69 -0,53
7.12.2011 1:00:00 -0,3 21,4 18,2 16,2 0 19,9 19,7 15,7 0,3 -1,5 1,5 -0,47
7.12.2011 2:00:00 -0,5 21,4 18,4 16,4 -0,79 20 19,7 15,9 -0,29 -1,4 1,3 -0,55
7.12.2011 3:00:00 -1,5 21,5 18,5 16,5 -1,15 20,2 19,68 16 0,35 -1,3 1,18 -0,55
7.12.2011 4:00:00 -2,6 21,6 18,6 16,7 -2,83 20,3 19,73 16,1 -0,23 -1,3 1,13 -0,58
7.12.2011 5:00:00 -2,2 21,7 18,7 16,8 -3,16 20,4 19,78 16,3 -0,96 -1,3 1,08 -0,53
7.12.2011 6:00:00 -2,5 21,8 18,9 17 -2,83 20,5 19,84 16,4 -0,33 -1,3 0,94 -0,57
7.12.2011 7:00:00 -2,4 22 19,1 17,2 -3,05 20,6 19,93 16,6 -0,65 -1,4 0,83 -0,58
7.12.2011 8:00:00 -3 15,5 21,5 5 -3,04 14,2 21,24 4,47 -0,04 -1,3 -0,26 -0,53
7.12.2011 9:00:00 -3,8 15,4 21,7 4,4 -3,86 13,2 21,55 2,83 -0,06 -2,2 -0,15 -1,57
7.12.2011 10:00:00 -4,1 15,2 21,5 4,1 -4,67 12,8 21,55 2,36 -0,57 -2,4 0,05 -1,74
7.12.2011 11:00:00 -3,4 15,3 21,5 4,5 -4,48 12,8 21,53 2,42 -1,08 -2,6 0,03 -2,08
7.12.2011 12:00:00 -2,9 15,4 21,6 5 -3,1 13,1 21,54 3,03 -0,2 -2,3 -0,06 -1,97
7.12.2011 13:00:00 -3,2 15,4 21,6 4,8 -2,7 13,1 21,51 3,08 0,5 -2,3 -0,09 -1,72
7.12.2011 14:00:00 -3,3 15,3 21,5 4,7 -2,7 13 21,51 2,83 0,6 -2,3 0,01 -1,87
7.12.2011 15:00:00 -2,9 15,4 21,5 4,9 -2,7 13,1 21,47 3,03 0,2 -2,3 -0,03 -1,87
7.12.2011 16:00:00 -2,3 15,5 21,5 5,3 -2,7 13,2 21,47 3,3 -0,4 -2,3 -0,03 -2
7.12.2011 17:00:00 -2 15,4 21,3 5,3 -2,7 13,3 21,34 3,54 -0,7 -2,1 0,04 -1,76
7.12.2011 18:00:00 -1,9 15,4 21,1 5,4 -1,96 13,3 21,2 3,62 -0,06 -2,2 0,1 -1,78
7.12.2011 19:00:00 -1,3 15,5 21 5,1 -2,4 13,4 20,94 3,31 -1,1 -2,1 -0,06 -1,79
7.12.2011 20:00:00 -0,7 15,7 20,9 5,5 -1,84 13,5 20,84 3,63 -1,14 -2,2 -0,06 -1,87
7.12.2011 21:00:00 -0,1 20,2 18,7 10,6 -1,29 15,4 20,67 6,36 -1,19 -4,8 1,97 -4,24
35
35
7.12.2011 22:00:00 0,1 20,6 17,5 13,8 -0,91 18,3 19,64 12,9 -1,01 -2,3 2,14 -0,9
7.12.2011 23:00:00 0,2 20,3 17,7 15,1 -0,78 18,6 19,49 14,5 -0,98 -1,8 1,79 -0,65
8.12.2011 0,3 20,4 17,9 15,8 -0,46 18,8 19,49 15,3 -0,76 -1,6 1,59 -0,54
8.12.2011 1:00:00 0,5 20,6 18,1 16,4 0,19 19,2 19,55 15,8 -0,31 -1,4 1,45 -0,6
8.12.2011 2:00:00 0,6 20,8 18,4 16,7 0,18 19,5 19,56 16,1 -0,42 -1,3 1,16 -0,63
8.12.2011 3:00:00 0,6 21 18,5 17 0,19 19,8 19,57 16,4 -0,41 -1,2 1,07 -0,63
8.12.2011 4:00:00 0,6 21,2 18,6 17,1 0,18 20 19,58 16,5 -0,42 -1,2 0,98 -0,58
8.12.2011 5:00:00 0,7 21,5 18,7 17,2 0,18 20,2 19,59 16,6 -0,52 -1,3 0,89 -0,58
8.12.2011 6:00:00 0,8 21,6 18,8 17,4 0,41 20,3 19,61 16,8 -0,39 -1,3 0,81 -0,61
8.12.2011 7:00:00 1 21,7 19 17,5 0,52 20,5 19,67 16,9 -0,48 -1,2 0,67 -0,57
8.12.2011 8:00:00 0,8 16,2 21,2 7,4 0,52 15,2 21,05 6,67 -0,28 -1 -0,15 -0,73
8.12.2011 9:00:00 0,7 16,2 21,4 7,4 0,52 14,4 21,27 5,71 -0,18 -1,8 -0,13 -1,69
8.12.2011 10:00:00 0,8 16,5 21,6 7,6 0,52 14,5 21,48 5,84 -0,28 -2 -0,12 -1,76
8.12.2011 11:00:00 1 16,4 21,5 7,5 0,51 14,5 21,41 5,92 -0,49 -1,9 -0,09 -1,58
8.12.2011 12:00:00 0,8 16,4 21,5 7,4 0,52 14,5 21,41 5,78 -0,28 -1,9 -0,09 -1,62
8.12.2011 13:00:00 0,6 16,2 21,5 7,3 0,76 14,4 21,45 5,69 0,16 -1,8 -0,05 -1,61
8.12.2011 14:00:00 0,7 16,2 21,5 7,4 0,83 14,4 21,48 5,7 0,13 -1,8 -0,02 -1,7
8.12.2011 15:00:00 0,5 16,1 21,5 7,1 0,79 14,3 21,38 5,65 0,29 -1,8 -0,12 -1,45
8.12.2011 16:00:00 0,1 16 21,4 6,8 0,37 14,1 21,26 5,29 0,27 -1,9 -0,14 -1,51
8.12.2011 17:00:00 0,3 15,9 21,2 6,9 -0,33 14 21,16 5,15 -0,63 -1,9 -0,04 -1,75
8.12.2011 18:00:00 0,3 15,9 21,1 6,9 -0,34 14 21,03 5,29 -0,64 -1,9 -0,07 -1,61
8.12.2011 19:00:00 0 16 21,1 6,1 -0,33 14 20,85 4,56 -0,33 -2 -0,25 -1,54
8.12.2011 20:00:00 -0,1 16,1 21,1 6,1 -0,28 14,2 20,95 4,51 -0,18 -2 -0,15 -1,59
8.12.2011 21:00:00 0,4 22,1 17,3 12,4 -0,29 18,6 20,06 10,1 -0,69 -3,5 2,76 -2,29
8.12.2011 22:00:00 0,5 21,4 17,6 14,6 -0,27 19,2 19,68 13,9 -0,77 -2,2 2,08 -0,75
8.12.2011 23:00:00 0,4 21 17,9 15,7 0,5 19,3 19,67 15,1 0,1 -1,7 1,77 -0,57
9.12.2011 0,5 21 18,2 16,2 0,47 19,5 19,67 15,7 -0,03 -1,5 1,47 -0,54
9.12.2011 1:00:00 0,6 21,1 18,5 16,7 0,47 19,7 19,68 16,1 -0,13 -1,4 1,18 -0,59
9.12.2011 2:00:00 0,6 21,4 18,7 17,1 0,51 20 19,69 16,4 -0,09 -1,5 0,99 -0,66
9.12.2011 3:00:00 0,6 21,5 18,8 17,2 0,5 20,2 19,7 16,7 -0,1 -1,4 0,9 -0,53
9.12.2011 4:00:00 0,7 21,6 19 17,4 0,54 20,3 19,72 16,8 -0,16 -1,3 0,72 -0,58
9.12.2011 5:00:00 0,8 21,8 19,1 17,5 0,47 20,5 19,73 17 -0,33 -1,3 0,63 -0,55
9.12.2011 6:00:00 0,5 22 19,2 17,7 0,54 20,6 19,75 17,1 0,04 -1,4 0,55 -0,63
9.12.2011 7:00:00 0,7 22,1 19,4 17,9 0,57 20,7 19,86 17,2 -0,13 -1,4 0,46 -0,71
9.12.2011 8:00:00 0,4 16,5 21,6 7,3 0,57 15,2 21,26 6,59 0,17 -1,3 -0,34 -0,71
9.12.2011 9:00:00 0,3 16,2 21,6 7 0,57 14,4 21,58 5,45 0,27 -1,8 -0,02 -1,55
MAX 0,87 -0,9 3,22 -0,47
MIN -1,79 -4,8 -0,41 -4,24
36
36
Appendix 2. Annual energy efficiency of rotating wheel heat recovery
tu Time
period Time in hours tpLTO ttLTO actual ttLTO RLTO t p Qexh air QLTO Qwc
C % h C C C kWh kWh kWh
-35 0,00 0 -5,0 -11,6 -11,6 1,11 0,42 0,46 0 0 0
-34 0,06 5 -5,0 -10,6 -10,6 1,11 0,43 0,47 424 200 132
-33 0,08 2 -5,0 -9,6 -9,6 1,11 0,43 0,48 168 81 52
-32 0,09 1 -5,0 -8,6 -8,6 1,11 0,44 0,49 79 39 25
-31 0,17 7 -5,0 -7,6 -7,6 1,11 0,45 0,50 562 281 175
-30 0,26 8 -5,0 -6,6 -6,6 1,11 0,46 0,51 634 323 197
-29 0,38 10 -5,0 -5,6 -5,6 1,11 0,47 0,52 770 401 240
-28 0,55 15 -5,0 -4,6 -4,6 1,11 0,48 0,53 1132 601 352
-27 0,75 18 -5,0 -3,6 -3,6 1,11 0,49 0,54 1330 720 414
-26 0,90 13 -5,0 -2,6 -2,6 1,11 0,50 0,55 946 524 294
-25 1,21 27 -5,0 -1,6 -1,6 1,11 0,51 0,57 1915 1082 596
-24 1,55 30 -5,0 -0,6 -0,6 1,11 0,52 0,58 2086 1205 649
-23 1,98 37 -5,0 0,4 0,4 1,11 0,53 0,59 2510 1483 781
-22 2,43 40 -5,0 1,4 1,4 1,11 0,54 0,60 2656 1606 826
-21 2,91 42 -5,0 2,4 2,4 1,11 0,56 0,62 2719 1683 846
-20 3,37 40 -5,0 3,4 3,4 1,11 0,57 0,63 2532 1606 788
-19 3,98 54 -5,0 4,4 4,4 1,11 0,59 0,65 3330 2165 1036
-18 4,75 67 -5,0 5,4 5,4 1,11 0,60 0,67 4032 2688 1255
-17 5,73 86 -5,0 6,4 6,4 1,11 0,62 0,68 5043 3451 1569
-16 6,96 108 -5,0 7,4 7,4 1,11 0,63 0,70 6161 4329 1917
-15 7,74 68 -5,0 8,4 8,4 1,11 0,65 0,72 3781 2730 1176
-14 8,40 58 -5,0 9,4 9,4 1,11 0,67 0,74 3132 2326 974
-13 9,06 58 -5,0 10,4 10,4 1,11 0,69 0,76 3042 2326 946
-12 9,68 54 -5,0 11,4 11,4 1,11 0,71 0,79 2747 2165 855
-11 10,45 67 -5,0 12,4 12,4 1,11 0,73 0,81 3330 2706 1036
-10 11,95 131 -5,0 13,4 13,4 1,11 0,75 0,84 6285 5271 1955
-9 13,32 120 -5,0 14,4 14,4 1,11 0,78 0,87 5555 4814 1728
-8 14,51 104 -4,6 15,1 15,1 1,11 0,80 0,88 4664 4124 1451
-7 15,96 127 -3,8 15,3 15,3 1,11 0,80 0,88 5487 4852 1707
-6 17,71 153 -2,9 15,5 15,5 1,11 0,80 0,88 6386 5647 1987
-5 19,90 192 -2,0 15,7 15,7 1,11 0,80 0,88 7696 6805 2394
-4 22,91 264 -1,1 15,9 15,9 1,11 0,80 0,88 10170 8993 3164
-3 26,29 296 -0,2 16,1 16,1 1,11 0,80 0,88 10964 9694 3411
-2 29,10 246 0,7 16,3 16,3 1,11 0,80 0,88 8735 7724 2718
-1 32,93 336 1,5 16,5 16,5 1,11 0,80 0,88 11388 10069 3543
0 38,18 460 2,4 16,7 16,7 1,11 0,80 0,88 14901 13175 4636
1 45,47 639 3,3 16,9 16,9 1,11 0,80 0,88 19705 17424 6131
2 50,21 415 4,2 17,0 17,1 1,11 0,79 0,88 12172 10677 3787
3 54,03 335 5,1 17,0 17,3 1,11 0,78 0,86 9293 8031 2891
4 56,95 256 6,0 17,0 17,5 1,11 0,76 0,85 6709 5701 2087
5 59,39 214 6,9 17,0 17,7 1,11 0,75 0,83 5276 4397 1642
6 62,07 235 7,7 17,0 17,9 1,11 0,73 0,81 5433 4427 1690
7 63,95 165 8,6 17,0 18,1 1,11 0,71 0,79 3557 2823 1107
8 65,96 176 9,5 17,0 18,3 1,11 0,69 0,77 3532 2717 1099
9 68,37 211 10,4 17,0 18,5 1,11 0,67 0,74 3909 2895 1216
10 70,88 220 11,3 17,0 18,8 1,11 0,64 0,71 3732 2639 1161
11 73,74 251 12,2 17,0 19,0 1,11 0,60 0,67 3865 2577 1203
12 76,39 232 13,0 17,0 19,2 1,11 0,56 0,62 3223 1990 1003
37
37
13 79,26 251 13,9 17,0 19,4 1,11 0,50 0,56 3103 1724 965
14 82,74 305 14,8 17,0 19,6 1,11 0,43 0,48 3292 1568 1024
15 85,79 267 15,7 17,0 19,8 1,11 0,33 0,37 2473 916 769
16 88,69 254 16,6 17,0 20,0 1,11 0,20 0,22 1960 435 610
17 91,07 208 17,5 17,0 20,2 1,11 0,00 0,00 1287 0 400
18 93,24 190 18,3 17,0 20,4 1,11 0,00 0,00 880 0 274
19 94,90 145 19,2 17,0 20,6 1,11 0,00 0,00 449 0 140
20 96,35 127 20,1 17,0 20,8 1,11 0,00 0,00 196 0 61
21 97,52 102 21,0 17,0 21,0 1,11 0,00 0,00 0 0 0
22 98,39 76 21,9 17,0 21,2 1,11 0,00 0,00 0 0 0
23 99,00 53 22,8 17,0 21,4 1,11 0,00 0,00 0 0 0
24 99,35 31 23,7 17,0 21,6 1,11 0,00 0,00 0 0 0
25 99,69 30 24,5 17,0 21,8 1,11 0,00 0,00 0 0 0
26 99,86 15 25,4 17,0 22,0 1,11 0,00 0,00 0 0 0
27 99,95 8 26,3 17,0 22,2 1,11 0,00 0,00 0 0 0
28 100,00 4 27,2 17,0 22,4 1,11 0,00 0,00 0 0 0
8760
241340 188830 75084
38
38
Appendix 3. Total annual efficiency of ventilation equipped with rotating wheel heat recovery
Month Mean tu
Time in
hours ttLTO Qiv Qiv, supply Qiv, make-up QLTO
°C h °C kWh kWh kWh kWh
January -3,97 650 10,93 6762,43 4457,14 2782,37 16604,14
February -4,50 602 10,72 6483,61 4128,00 2631,60 15704,39
March -2,58 607 11,49 5731,83 4162,29 2453,67 14642,56
April 4,50 354 14,35 1610,25 2427,43 1001,31 5975,46
May 10,76 117 16,87 25,90 802,29 205,39 1225,66
June 14,23 9 18,27 0,00 61,71 10,45 62,33
July 17,30 0 19,51 0,00 0,00 0,00 0,00
August 16,05 31 19,00 0,00 212,57 26,31 156,98
September 10,53 161 16,78 61,24 1104,00 288,97 1724,48
October 6,20 331 15,03 1116,65 2269,71 839,79 5011,57
November 0,50 495 12,73 3620,33 3394,29 1739,57 10381,10
December -2,19 595 11,65 5458,11 4080,00 2365,38 14115,69
30870,36 27099,43 14344,81 85604,37
39
39
Appendix 4. Annual energy efficiency of counter-flow plate heat recovery
tu Time
period
Time in
hours tpLTO
ttLTO
actual ttLTO RLTO ƞt ƞp Qexh day Qexh night Qexh we QLTO day QLTO night QLTO we
°C % h °C °C °C kWh kWh kWh kWh kWh kWh
-35 0,00 0 0,0 -14,0 -14,0 1 0,38 0,38 0 0 0 0 0 0
-34 0,06 5 0,0 -13,0 -13,0 1 0,38 0,38 471 47 38 180 18 14
-33 0,08 2 0,0 -12,0 -12,0 1 0,39 0,39 187 19 15 73 7 6
-32 0,09 1 0,0 -11,0 -11,0 1 0,40 0,40 88 9 7 35 3 3
-31 0,17 7 0,0 -10,0 -10,0 1 0,40 0,40 625 62 50 252 25 20
-30 0,26 8 0,0 -9,0 -9,0 1 0,41 0,41 705 70 56 290 29 23
-29 0,38 10 0,0 -8,0 -8,0 1 0,42 0,42 856 86 68 360 36 29
-28 0,55 15 0,0 -7,0 -7,0 1 0,43 0,43 1258 126 101 539 54 43
-27 0,75 18 0,0 -6,0 -6,0 1 0,44 0,44 1478 148 118 646 65 52
-26 0,90 13 0,0 -5,0 -5,0 1 0,45 0,45 1052 105 84 470 47 38
-25 1,21 27 0,0 -4,0 -4,0 1 0,46 0,46 2128 213 170 971 97 78
-24 1,55 30 0,0 -3,0 -3,0 1 0,47 0,47 2318 232 185 1082 108 87
-23 1,98 37 0,0 -2,0 -2,0 1 0,48 0,48 2788 279 223 1331 133 106
-22 2,43 40 0,0 -1,0 -1,0 1 0,49 0,49 2951 295 236 1441 144 115
-21 2,91 42 0,0 0,0 0,0 1 0,50 0,50 3021 302 242 1511 151 121
-20 3,37 40 0,0 1,0 1,0 1 0,51 0,51 2814 281 225 1441 144 115
-19 3,98 54 0,0 2,0 2,0 1 0,53 0,53 3700 370 296 1943 194 155
-18 4,75 67 0,0 3,0 3,0 1 0,54 0,54 4480 448 358 2413 241 193
-17 5,73 86 0,0 4,0 4,0 1 0,55 0,55 5604 560 448 3097 310 248
-16 6,96 108 0,0 5,0 5,0 1 0,57 0,57 6845 685 548 3885 389 311
-15 7,74 68 0,0 6,0 6,0 1 0,58 0,58 4201 420 336 2450 245 196
-14 8,40 58 0,0 7,0 7,0 1 0,60 0,60 3479 348 278 2088 209 167
-13 9,06 58 0,0 8,0 8,0 1 0,62 0,62 3380 338 270 2088 209 167
-12 9,68 54 0,0 9,0 9,0 1 0,64 0,64 3053 305 244 1943 194 155
-11 10,45 67 0,0 10,0 10,0 1 0,66 0,66 3700 370 296 2428 243 194
40
40
-10 11,95 131 0,0 11,0 11,0 1 0,68 0,68 6983 698 559 4730 473 378
-9 13,32 120 0,0 12,0 12,0 1 0,70 0,70 6172 617 494 4320 432 346
-8 14,51 104 0,7 12,3 12,3 1 0,70 0,70 5182 518 415 3628 363 290
-7 15,96 127 1,4 12,6 12,6 1 0,70 0,70 6097 610 488 4268 427 341
-6 17,71 153 2,1 12,9 12,9 1 0,70 0,70 7096 710 568 4967 497 397
-5 19,90 192 2,8 13,2 13,2 1 0,70 0,70 8551 855 684 5986 599 479
-4 22,91 264 3,5 13,5 13,5 1 0,70 0,70 11300 1130 904 7910 791 633
-3 26,29 296 4,2 13,8 13,8 1 0,70 0,70 12182 1218 975 8527 853 682
-2 29,10 246 4,9 14,1 14,1 1 0,70 0,70 9706 971 776 6794 679 544
-1 32,93 336 5,6 14,4 14,4 1 0,70 0,70 12653 1265 1012 8857 886 709
0 38,18 460 6,3 14,7 14,7 1 0,70 0,70 16556 1656 1325 11589 1159 927
1 45,47 639 7,0 15,0 15,0 1 0,70 0,70 21895 2189 1752 15326 1533 1226
2 50,21 415 7,7 15,3 15,3 1 0,70 0,70 13524 1352 1082 9467 947 757
3 54,03 335 8,4 15,6 15,6 1 0,70 0,70 10326 1033 826 7228 723 578
4 56,95 256 9,1 15,9 15,9 1 0,70 0,70 7455 745 596 5218 522 417
5 59,39 214 9,8 16,2 16,2 1 0,70 0,70 5863 586 469 4104 410 328
6 62,07 235 10,5 16,5 16,5 1 0,70 0,70 6037 604 483 4226 423 338
7 63,95 165 11,2 16,8 16,8 1 0,70 0,70 3953 395 316 2767 277 221
8 65,96 176 11,9 17,0 17,1 1 0,69 0,69 3924 392 314 2717 272 217
9 68,37 211 12,6 17,0 17,4 1 0,67 0,67 4343 434 347 2895 290 232
10 70,88 220 13,3 17,0 17,7 1 0,64 0,64 4146 415 332 2639 264 211
11 73,74 251 14,0 17,0 18,0 1 0,60 0,60 4295 429 344 2577 258 206
12 76,39 232 14,7 17,0 18,3 1 0,56 0,56 3582 358 287 1990 199 159
13 79,26 251 15,4 17,0 18,6 1 0,50 0,50 3448 345 276 1724 172 138
14 82,74 305 16,1 17,0 18,9 1 0,43 0,43 3658 366 293 1568 157 125
15 85,79 267 16,8 17,0 19,2 1 0,33 0,33 2748 275 220 916 92 73
16 88,69 254 17,5 17,0 19,5 1 0,20 0,20 2177 218 174 435 44 35
17 91,07 208 18,2 17,0 19,8 1 0,00 0,00 1430 143 114 0 0 0
18 93,24 190 18,9 17,0 20,1 1 0,00 0,00 978 98 78 0 0 0
19 94,90 145 19,6 17,0 20,4 1 0,00 0,00 499 50 40 0 0 0
20 96,35 127 20,3 17,0 20,7 1 0,00 0,00 218 22 17 0 0 0
21 97,52 102 21,0 17,0 21,0 1 0,00 0,00 0 0 0 0 0 0
41
41
22 98,39 76 21,7 17,0 21,3 1 0,00 0,00 0 0 0 0 0 0
23 99,00 53 22,4 17,0 21,6 1 0,00 0,00 0 0 0 0 0 0
24 99,35 31 23,1 17,0 21,9 1 0,00 0,00 0 0 0 0 0 0
25 99,69 30 23,8 17,0 22,2 1 0,00 0,00 0 0 0 0 0 0
26 99,86 15 24,5 17,0 22,5 1 0,00 0,00 0 0 0 0 0 0
27 99,95 8 25,2 17,0 22,8 1 0,00 0,00 0 0 0 0 0 0
28 100,00 4 25,9 17,0 23,1 1 0,00 0,00 0 0 0 0 0 0
8760
268156 26816 21452 170329 17033 13626
316424 200988
42
42
Appendix 5. Total annual efficiency of ventilation equipped with counter-flow plate heat
recovery
Month Mean tu
Time in
hours ttLTO Qiv Qiv, supply QLTO
°C h °C kWh kWh kWh
January -3,97 650 11,89 5693,30 4457,14 17673,27
February -4,50 602 11,70 5472,41 4128,00 16715,59
March -2,58 607 12,40 4789,01 4162,29 15585,38
April 4,50 354 14,98 1225,49 2427,43 6360,22
May 10,76 117 17,26 0,00 802,29 1304,58
June 14,23 9 18,53 0,00 61,71 66,35
July 17,30 0 19,65 0,00 0,00 0,00
August 16,05 31 19,19 0,00 212,57 167,09
September 10,53 161 17,18 0,00 1104,00 1835,51
October 6,20 331 15,60 793,96 2269,71 5334,27
November 0,50 495 13,52 2951,89 3394,29 11049,54
December -2,19 595 12,54 4549,21 4080,00 15024,59
25475,28 27099,43 91116,38
43
43
Appendix 6. Annual energy efficiency of cross-flow plate heat recovery
tu
Time
period
Time in
hours tpLTO
ttLTO
actual ttLTO RLTO ƞt ƞp Qexh day Qexh night Qexh we QLTO day QLTO night QLTO we
°C % h °C °C °C kWh kWh kWh kWh kWh kWh
-35 0,00 0 0,0 -14,0 -14,0 1 0,38 0,38 0 0 0 0 0 0
-34 0,06 5 0,0 -13,0 -13,0 1 0,38 0,38 471 47 38 180 18 14
-33 0,08 2 0,0 -12,0 -12,0 1 0,39 0,39 187 19 15 73 7 6
-32 0,09 1 0,0 -11,0 -11,0 1 0,40 0,40 88 9 7 35 3 3
-31 0,17 7 0,0 -10,0 -10,0 1 0,40 0,40 625 62 50 252 25 20
-30 0,26 8 0,0 -9,0 -9,0 1 0,41 0,41 705 70 56 290 29 23
-29 0,38 10 0,0 -8,0 -8,0 1 0,42 0,42 856 86 68 360 36 29
-28 0,55 15 0,0 -7,0 -7,0 1 0,43 0,43 1258 126 101 539 54 43
-27 0,75 18 0,0 -6,0 -6,0 1 0,44 0,44 1478 148 118 646 65 52
-26 0,90 13 0,0 -5,0 -5,0 1 0,45 0,45 1052 105 84 470 47 38
-25 1,21 27 0,0 -4,0 -4,0 1 0,46 0,46 2128 213 170 971 97 78
-24 1,55 30 0,0 -3,0 -3,0 1 0,47 0,47 2318 232 185 1082 108 87
-23 1,98 37 0,0 -2,0 -2,0 1 0,48 0,48 2788 279 223 1331 133 106
-22 2,43 40 0,0 -1,0 -1,0 1 0,49 0,49 2951 295 236 1441 144 115
-21 2,91 42 0,0 0,0 0,0 1 0,50 0,50 3021 302 242 1511 151 121
-20 3,37 40 0,0 1,0 1,0 1 0,51 0,51 2814 281 225 1441 144 115
-19 3,98 54 0,0 2,0 2,0 1 0,53 0,53 3700 370 296 1943 194 155
-18 4,75 67 0,0 3,0 3,0 1 0,54 0,54 4480 448 358 2413 241 193
-17 5,73 86 0,1 3,9 3,9 1 0,55 0,55 5604 560 448 3082 308 247
-16 6,96 108 0,6 4,4 4,4 1 0,55 0,55 6845 685 548 3765 376 301
-15 7,74 68 1,2 4,8 4,8 1 0,55 0,55 4201 420 336 2310 231 185
-14 8,40 58 1,8 5,3 5,3 1 0,55 0,55 3479 348 278 1914 191 153
-13 9,06 58 2,3 5,7 5,7 1 0,55 0,55 3380 338 270 1859 186 149
-12 9,68 54 2,9 6,2 6,2 1 0,55 0,55 3053 305 244 1679 168 134
-11 10,45 67 3,4 6,6 6,6 1 0,55 0,55 3700 370 296 2035 204 163
-10 11,95 131 4,0 7,1 7,1 1 0,55 0,55 6983 698 559 3841 384 307
44
44
-9 13,32 120 4,5 7,5 7,5 1 0,55 0,55 6172 617 494 3395 339 272
-8 14,51 104 5,1 8,0 8,0 1 0,55 0,55 5182 518 415 2850 285 228
-7 15,96 127 5,6 8,4 8,4 1 0,55 0,55 6097 610 488 3353 335 268
-6 17,71 153 6,2 8,9 8,9 1 0,55 0,55 7096 710 568 3903 390 312
-5 19,90 192 6,7 9,3 9,3 1 0,55 0,55 8551 855 684 4703 470 376
-4 22,91 264 7,3 9,8 9,8 1 0,55 0,55 11300 1130 904 6215 622 497
-3 26,29 296 7,8 10,2 10,2 1 0,55 0,55 12182 1218 975 6700 670 536
-2 29,10 246 8,4 10,7 10,7 1 0,55 0,55 9706 971 776 5338 534 427
-1 32,93 336 8,9 11,1 11,1 1 0,55 0,55 12653 1265 1012 6959 696 557
0 38,18 460 9,5 11,6 11,6 1 0,55 0,55 16556 1656 1325 9106 911 728
1 45,47 639 10,0 12,0 12,0 1 0,55 0,55 21895 2189 1752 12042 1204 963
2 50,21 415 10,6 12,5 12,5 1 0,55 0,55 13524 1352 1082 7438 744 595
3 54,03 335 11,1 12,9 12,9 1 0,55 0,55 10326 1033 826 5679 568 454
4 56,95 256 11,7 13,4 13,4 1 0,55 0,55 7455 745 596 4100 410 328
5 59,39 214 12,2 13,8 13,8 1 0,55 0,55 5863 586 469 3224 322 258
6 62,07 235 12,8 14,3 14,3 1 0,55 0,55 6037 604 483 3320 332 266
7 63,95 165 13,3 14,7 14,7 1 0,55 0,55 3953 395 316 2174 217 174
8 65,96 176 13,9 15,2 15,2 1 0,55 0,55 3924 392 314 2158 216 173
9 68,37 211 14,4 15,6 15,6 1 0,55 0,55 4343 434 347 2389 239 191
10 70,88 220 15,0 16,1 16,1 1 0,55 0,55 4146 415 332 2280 228 182
11 73,74 251 15,5 16,5 16,5 1 0,55 0,55 4295 429 344 2362 236 189
12 76,39 232 16,1 17,0 17,0 1 0,55 0,55 3582 358 287 1970 197 158
13 79,26 251 16,6 17,0 17,4 1 0,50 0,50 3448 345 276 1724 172 138
14 82,74 305 17,2 17,0 17,9 1 0,43 0,43 3658 366 293 1568 157 125
15 85,79 267 17,7 17,0 18,3 1 0,33 0,33 2748 275 220 916 92 73
16 88,69 254 18,3 17,0 18,8 1 0,20 0,20 2177 218 174 435 44 35
17 91,07 208 18,8 17,0 19,2 1 0,00 0,00 1430 143 114 0 0 0
18 93,24 190 19,4 17,0 19,7 1 0,00 0,00 978 98 78 0 0 0
19 94,90 145 19,9 17,0 20,1 1 0,00 0,00 499 50 40 0 0 0
20 96,35 127 20,5 17,0 20,6 1 0,00 0,00 218 22 17 0 0 0
21 97,52 102 21,0 17,0 21,0 1 0,00 0,00 0 0 0 0 0 0
22 98,39 76 21,6 17,0 21,5 1 0,00 0,00 0 0 0 0 0 0
45
45
23 99,00 53 22,1 17,0 21,9 1 0,00 0,00 0 0 0 0 0 0
24 99,35 31 22,7 17,0 22,4 1 0,00 0,00 0 0 0 0 0 0
25 99,69 30 23,2 17,0 22,8 1 0,00 0,00 0 0 0 0 0 0
26 99,86 15 23,8 17,0 23,3 1 0,00 0,00 0 0 0 0 0 0
27 99,95 8 24,3 17,0 23,7 1 0,00 0,00 0 0 0 0 0 0
28 100,00 4 24,9 17,0 24,2 1 0,00 0,00 0 0 0 0 0 0
8760
268156 26816 21452 141765 14176 11341
316424 167283
46
46
Appendix 7. Total annual efficiency of ventilation equipped with cross-flow plate heat recovery
Month Mean tu
Time in
hours ttLTO Qiv Qiv, supply QLTO
°C h °C kWh kWh kWh
January -3,97 650 9,23 8657,10 4457,14 14709,47
February -4,50 602 8,98 8275,61 4128,00 13912,39
March -2,58 607 9,89 7402,67 4162,29 12971,72
April 4,50 354 13,22 2292,10 2427,43 5293,61
May 10,76 117 16,17 165,76 802,29 1085,80
June 14,23 9 17,81 0,00 61,71 55,22
July 17,30 0 19,26 0,00 0,00 0,00
August 16,05 31 18,67 0,00 212,57 139,07
September 10,53 161 16,07 258,02 1104,00 1527,70
October 6,20 331 14,02 1688,52 2269,71 4439,71
November 0,50 495 11,34 4804,90 3394,29 9196,53
December -2,19 595 10,07 7068,83 4080,00 12504,97
40613,51 27099,43 75836,20
